This invention relates to a pull-on disposable diaper for absorption and containment of body wastes.
Japanese Patent Application Disclosure Gazette (Kokai) No. Hei5-15551 discloses a pull-on disposable diaper in which front and rear waist regions comprising a topsheet and a backsheet containing heat-sealable materials are placed upon each other along their respective side edges and heat-sealed together at heat-sealing spots intermittently arranged on the side edges vertically of the diaper. A wearer of such diaper can be stripped thereof by tearing the diaper from top to bottom along the respective arrays of the heat-sealing spots so that the front and rear waist regions may be separated from each other forth and back. By stripping the wearer of the diaper in this manner, the wearer""s legs can be protected from being soiled with body wastes.
With the pull-on disposable diaper according to the above-mentioned prior art, if the topsheet and/or the backsheet are fiber-oriented transversely of the diaper, the lines along which the diaper should be torn are apt to turn aside following the fiber orientation in the course of tearing the diaper vertically thereof. Such a tendency often makes it difficult to tear off the diaper in an orderly manner.
In view of the problem as has been described above, it is an object of the present invention to provide a pull-on disposable diaper having front and rear waist regions placed upon and bonded to each other along their respective side edges improved so that the diaper may be torn off in a relatively easy manner in the vertical direction.
According to the present invention, there is provided a pull-on disposable diaper having a front waist region and a rear waist region, the diaper comprising a liquid-pervious topsheet, a liquid-impervious backsheet and a liquid-absorbent core disposed between the topsheet and the backsheet, each of transversely opposed side edges of the front and rear waist regions being placed upon each other and bonded together at an outer bonding zone intermittently arranged on each of the side edges in a vertical direction of the diaper.
Each of the side edges of the front and rear waist regions bonded together comprises a plurality of sheet materials placed one upon another, the plurality of sheet materials being bonded together along an inner bonding line extending in parallel to the outer bonding line at each of the front and rear waist regions, with said inner bonding line being spaced inwardly from the outer bonding line by 3xcx9c20 mm.
According to one preferred embodiment of the present invention, at least one of the plurality of sheet materials contains thermoplastic synthetic resin, the inner bonding line is formed by heat-sealing the thermoplastic synthetic resin.
According to another preferred embodiment of the present invention, the plurality of sheet materials placed one upon another along each of the side edges comprise the topsheet and the backsheet.
According to still another preferred embodiment of the present invention, one of the topsheet and the backsheet includes a nonwoven fabric fiber-oriented transversely of the diaper.
According to further another preferred embodiment of the present invention, the backsheet is a laminate sheet comprising a thermoplastic synthetic resin film as an inner layer and a nonwoven fabric of thermoplastic synthetic resin as an outer layer.